The present invention relates to electrical adapters for distributorless ignition systems; more particularly, the present invention relates to an adapter for use between a spark plug cable and a high output terminal of a distributorless ignition system.
Prior art automotive ignition systems relied upon a distributor to deliver energy to spark plugs at given intervals. In a distributorless ignition system, the timing function is computerized and each spark plug is attached to a separate high energy output terminal which delivers energy at the proper interval, eliminating the need for a distributor.
Typically, the distributorless ignition system (D.I.S.) includes multiple terminals, each of which include a cup-shaped electrode and a tower extending upward from the electrode. The spark plug cable must be connected to the high output terminal to deliver energy to the spark plug located at the opposite end of the spark plug cable. The connection means between the cable and the terminal must provide an electrical as well as a water-tight mechanical connection. Prior art adapters designed for connecting the spark plug cable to the high output terminal of a D.I.S. include the device disclosed in U.S. Pat. No. 4,790,767 to Sturdevan. The device described in this patent is a cap-like arrangement with an annular recess that fits over the top of the tower to effect a water-tight seal. Mechanical connection is made with levered dogs which grip a flange formed at the outside of the tower. Electrical connection in the device described in U.S. Pat. No. 4,790,767 is by a terminal which fits within the cupshaped electrode of the D.I.S.
One disadvantage of the adapter disclosed in U.S. Pat. No. 4,790,767 is its reliance on the external shape of the tower for a proper connection and water-tight seal. While present distributorless systems like those utilized by Ford Motor Company include a flanged tower, future D.I.S. designs may not have flanged towers and may require internal connections and sealing. Additionally, as space becomes more important in automotive designing, future distributorless systems may require the output terminals to be spaced closer together making it impracticable to use an adapter which grips the outside of the tower.
There is a need, therefore, for an adapter for a distributorless ignition system which does not utilize the outside perimeter of the tower for mechanical connection or water-tight sealing.
There is a further need, therefore, for an adapter for a distributorless ignition system which requires less space than those presently available.